Anopheles coluzzii larval response to two purified Pseudomonas aeruginosa phenazine pigments 1-HP and Pyo.. Anopheles coluzzii

Pseudomonas aeruginosa, the type species of the Pseudomonas genus, is an environmental Gram negative bacterium, well-known for its ability to produce toxins, resist antibiotics, and opportunistically colonize various niches, including invertebrate and vertebrate hosts. P. aeruginosa produces redox active secondary metabolites called phenazines involved in quorum sensing, biofilm formation, virulence, and iron acquisition. Moreover, these colorful pigmented virulence factors act as ligands for the highly conserved aryl hydrocarbon receptor (AhR) thereby regulating antibacterial defenses in vertebrates. Pseudomonas spp. are some of the most frequently identified bacteria in larval and adult stages of wild mosquito populations. Here we investigated global transcriptional changes induced in A. coluzzii third instar larvae incubated with a sublethal concentration (50 µM) of 1-hydroxyphenazine (1-HP) or pyocyanin (Pyo) at 4 h and 8 h of continuous incubation by whole-genome DNA microarrays. Overall design: Two experimental replicates (containing 15 pooled third instar larvae each) of 1-hydroxyphenazine (1-HP, 50 µM), pyocyanin (Pyo, 50 µM) or DMSO (50 µM equivalent volume) control; two timepoints of 4 h and 8 h. Microarray experiments were performed as dual-color hybridizations with color-swap dye-reversal (=two technical replicates for each sample). 1-HP or Pyo treatment samples were hybridized with respective DMSO controls. Total samples: 3 treatments * 2 experimental replicates * 2 timepoints = 12 samples; Total hybridizations: 2 comparisons * 2 experimental replicates * 2 timepoints * 2 technical replicates = 16 hybridizations.